Field of the Invention
The present invention relates to a radiation imaging apparatus, a method of determining radiation irradiation, and a storage medium.
Description of the Related Art
Recently, an FPD (flat panel detector) has been put into practical use. In this FPD, a phosphor is arranged on a TFT active matrix substrate, and radiation is accumulated as a charge signal and converted into a digital signal, thereby providing a diagnostic image.
If the FPD is used as the imaging medium of a modality, it may become difficult to establish an interface between a radiation generation apparatus and the FPD. As a method to cope with this, for example, Japanese Patent Laid-Open Nos. 2012-083307 and 2011-185622 propose an FPD which detects the start of radiation irradiation on an FPD side and automatically starts an accumulation operation without providing an interface between a radiation generation apparatus and the FPD.
For example, Japanese Patent Laid-Open No. 2012-083307 proposes a technique of controlling a threshold based on a TFT temperature at the time of selecting an imaging menu, and Japanese Patent Laid-Open No. 2011-185622 proposes a technique of controlling a threshold based on a VS signal value at the time of a reset operation.
In the method of setting the threshold according to each conventional technique, a uniform threshold is set even if a plurality of FPDs (detection apparatuses) are used. For this reason, if the characteristics of the detection apparatuses change locally due to an external environment, it exerts an influence on the detection accuracy of all the plurality of detection apparatuses, and thus the improvement of the detection accuracy of detecting the presence/absence of radiation irradiation is limited.
The present invention provides a technique capable of detecting the presence/absence of radiation irradiation appropriately even if the external environment changes locally.